String texto="Rojo"+arrayList.get(i);

String texto="33[31m Rojo"+arrayList.get(i);

String texto="Rojo"+arrayList.get(i);

String texto="<font color="#ff0000">Rojo</font>"+"<font color="#000000">"+ arrayList.get(i) + "</font>";

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    textView.setText(Html.fromHtml(texto, Html.FROM_HTML_MODE_LEGACY));
} else {
  textView.setText(Html.fromHtml(texto));
}